Scribe Line Segmentation for Wafer Sawing Yield
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Solution Overview
Problem
The challenge in semiconductor wafer fabrication is the mechanical strength difference between metal test pads and low-k dielectric layers during the sawing process, leading to lamination or crack issues due to the blade resistance, which affects yield and throughput.
Innovation Solution
The implementation of a scribe line structure with metal-pattern containing scribe lines (used for probing) and metal-pattern free scribe lines (used for sawing), where the sawing process only occurs through the metal-pattern free scribe lines, reducing the likelihood of damage to low-k dielectric layers and particle issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If test pads are formed in scribe lines for wafer testing, then testing capability is improved, but mechanical strength difference causes lamination or crack during sawing
Solution Approach 1:
The scribe line is segmented into two distinct types: metal-pattern containing scribe lines for testing and metal-pattern free scribe lines for sawing. This segmentation allows each zone to be optimized for its specific function, preventing the mechanical strength conflict that occurs when both testing and sawing share the same scribe line structure.
Solution Approach 2:
Different regions of the scribe line are assigned different material compositions and structures. The metal-pattern containing regions provide electrical connectivity for testing, while the metal-pattern free regions provide uniform mechanical properties for sawing. This local differentiation resolves the contradiction between testing capability and mechanical strength uniformity.
2Productivity
If blade saws through metal test pads, then separation is achieved, but high resistance to blade causes lamination or crack in low-k dielectric layers
Solution Approach 1:
The metal patterns are extracted from the scribe lines that are designated for sawing. By removing the metal test pads from the metal-pattern free scribe lines, the blade encounters only uniform low-k dielectric material during sawing, eliminating the high resistance that causes lamination or cracking while maintaining the ability to separate wafers efficiently.
3Reliability
If metal patterns are included in all scribe lines for testing, then testing is enabled, but particle issues and damage occur during sawing
Solution Approach 1:
The scribe line network is segmented into metal-pattern containing scribe lines for testing and metal-pattern free scribe lines for sawing. This segmentation ensures that metal patterns remain in testing zones where they are needed, while being completely removed from sawing zones, thereby eliminating particle generation during the sawing process.
Data Source
AI summary
A wafer includes a plurality of chips arranged as rows and columns. A first plurality of scribe lines is between the rows of the plurality of chips. Each of the first plurality of scribe lines includes a metal-feature containing scribe line comprising metal features therein, and a metal-feature free scribe line parallel to, and adjoining, the metal-feature containing scribe line. A second plurality of scribe lines is between the columns of the plurality of chips.